The invention relates to a method and apparatus for the slip-free hauling or heaving of a rope of similar, flexible power transmitting elements.
Hauling methods and arrangements are known in diverse forms and are used for various purposes. For example, such hauling devices are known from the German Patent Publications DOS 2,311,912 and DAS 1,556,458. The arrangements of DOS 2,311,912 include power transmission devices and are constructed a differential gear means. These devices are also provided with auxiliary brakes for the rope pay out. The apparatus of DAS 1,556,458 is constructed for performing an automatic adjustment to compensate for a horizontal shift of a boat or ship.
These prior art devices have their practical limitations expecially with regard to construction costs. In addition, these devices are restricted with regard to their installation and their use. Besides, the functional safety and reliability of operation of these known devices are often inadequate.
German Patent Publication DAS 1,028,454 discloses a capstan or windlass for sailing sheets which has two locking pawls working on a gear wheel connected to the capstan head. One of these locking pawls is pivoted or hingedly connected to a base plate. The other pawl is hingedly connected to an operating lever movable back and forth on a circular path. The operating lever, in turn is supported so that it is rotatable about the capstan journal. In this case, the capstan head and spur gear form an integral structure and turn about a journal. This journal, likewise, forms an integral structure with the base of the device. In this device, two spring-loaded holding or locking pawls engage the spur gear. However, such a device requires that the rope is looped completely around the capstan head at least once. The rope must even be looped around the capstan head several times if large forces are to be transmitted. In this case, the rope must also be fixed by a clamping device. Numerous accidents have been caused just be releasing the rope from the clamping device. The hands of the operator are placed in danger and may get clamped off or may get caught, particularly when higher forces and accelerations are involved.
The German Patent Publication DOS 2,155,904 discloses a sailing winch which is arranged for several speeds. The winch has a direct drive with two speed reductions. This winch comprises a rope hoisting drum, a drive shaft, and one hand crank. The hand crank drives the hoisting drum through the drive shaft by means of two wheel blocks or pulleys. These pulleys are connected to the drive shaft by a drive means which is effective in one direction. In addition, the pulleys also have a direct drive. This direct drive comprises one drive connection which operates in one direction, and liftable locking pawls, friction rollers or other mechanical connecting means. The rope hoisting drum is rotated in one defined direction by means of said hand crank.
All of the above arrangements or devices have numerous deficiencies. On the one hand, these devices require an auxiliary clamping and holding mechanism which tightens or holds the rope around the winch. On the other, a supplemental auxiliary force or helper is required even when relatively small forces are to be handled. Also, the rope must loop around the winch roller or drum several times to form several turns.
The German Patent Publication DOS 1,920,789 describes a winch block comprising a disengageable ratchet which blocks rotation in one direction in a form locking manner. The winch block also includes a rope pulley which allegedly receives the sheet in a self-locking manner. The rope pulley has at least one centrally arranged gear system. This gear system cooperates with at least one locking pawl that is capable of free tilting movement. Spring biasing means keep the locking pawl and gear engaged. A radial notch or recess which permits the free movement of the locking pawl, is arranged between a shoulder supporting the locking pawl in the radial direction and the following locking tooth. A shoulder is provided for each locking tooth and the teeth and shoulders are arranged on the same side of the rope pulley as viewed in the same circumferential direction of the pulley.
However, in such an arrangement the probability of proper engaging and disengaging of the locking pawl is small indeed. Hence the operation and reliability of this type of device leave room for improvement. On the other hand, this known device does not provide any self-locking worth mentioning since the rope slips through even with minimal loading forces. Such slipping of the rope must be expected because of the centrally arranged gear system.